Fig. 85: Identifying Sensor Mounting Flange, Threaded Mounting Stud, Stamped Metal Cage, Sensor
Body & Receptacle
Courtesy of CHRYSLER LLC
The seat weight sensors are strain gauge-type units. The electronic elements of the sensor are encased within the
sensor body (5) and the sensor body is located within a stamped metal cage (3). Four sensors are used in the
Occupant Classification System (OCS). The sensors are located below the seat cushion between the seat
adjuster track and the seat track riser at each corner of the passenger side front seat.
A threaded mounting stud (2) on each sensor body is secured by a nut to the seat track riser, and two nuts secure
each sensor mounting flange (1) to two studs integral to the front and rear of the inboard and outboard
passenger side lower seat adjuster tracks. A molded connector receptacle (4) integral to each sensor body is
oriented towards the center of the seat and is connected to the vehicle electrical system through a dedicated
connector and take out of the passenger seat wire harness beneath the seat cushion.
The seat weight sensors cannot be adjusted or repaired and, if ineffective or damaged, the entire sensor must be
replaced.
OPERATION
SEAT WEIGHT SENSOR
The seat weight sensor units are designed to sense the relative weight of a load applied to the passenger side
front seat, which provides a logic input to the microprocessor of the Occupant Classification Module (OCM).
When any load is applied to the seat the load is transmitted through the sensor mounting stud to the sensor body
(strain gauge) of each sensor, causing a change of electrical resistance through the strain gauge. These changes
in resistance within the internal sensor circuitry change the sensor output voltage.
Each weight sensor receives a nominal five volts and a ground through parallel hard wired circuits from the
OCM. The OCM then monitors the output voltage of each sensor on dedicated hard wired data communication
circuits. The OCM also monitors the condition of the sensor circuits and will store a Diagnostic Trouble Code
(DTC) for any fault that is detected, then send messages to the Occupant Restraint Controller (ORC) to
illuminate the airbag indicator in the Electro Mechanical Instrument Cluster (EMIC) (also known as the Cab
2007 Dodge Nitro R/T
2007 RESTRAINTS Service Information - Nitro